Fluid impervious liner for packing box



July 7, 1970 T. J. LORENZ, JR., ET AL 3,519,i%

FLUID IMPERVIOUS LINER FOR PACKING BOX Filed Aug. 19, 1968 2 Sheets-Sheet 1 /7 Attorneys July 7, 1970 T. J. LORENZ, JR. ET AL 3,519,160

FLUID IMPERVIOUS LINER FOR PACKING BOX Filed Aug. 19, 1968 2 Sheets-Sheet z INVENTCRS Theodore J. Lorenz, Jr. BY NIChOIOS V Poletiko florneys United States Patent 3,519,160 FLUID IMPERVIOUS LINER FOR PACKING BOX Theodore J. Lorenz, Jr., and Nicholas V. Poletika, Fort Bragg, Calif, assignors to Union Lumber Company, Fort Bragg, Calif, a corporation of California Filed Aug. 19, 1968, Ser. No. 753,470 Int. Cl. B65d 25/14 U.S. Cl. 217-3 4 Claims ABSTRACT OF THE DISCLOSURE A plastic liner for a fruit packing box which is folded polyethylene film glued to a supporting pad of similar dimensions which orients the liner in the box. The low coeflicient of kinetic friction of the polyethylene film provides for easy unfolding.

BACKGROUND OF THE INVENTION The present invention is directed to a liner for packing boxes and more specifically to a fluid impervious liner useful in packing fruit.

In the packing and shipping of fruits it is necessary both to mechanically cushion the fruit from impacts which would produce surface imperfections and damage and, in addition, to preserve the water content of the fruit.

The latter is of special importance in the case of smooth skinned fruits such as nectarines which loose their water content relatively rapidly. One method of retaining the fruits moisture content is to pack them in a fluid impervious box. In addition, for grapes and similar fruits,

it is desirable to provide a protective atmosphere (e.g.,

sulphur dioxide). Retention of such atmosphere also requires a fluid impervious box.

To provide a fluid impervious packing box, plastic liners have been used. Stacked sheets of plastic are placed next to the packing box and the fruit packer carefully removes a sheet from the stack and orients it in the box, making certain that the ends of the sheet which serve as closure flaps are equal in length. Such procedures are time consuming and introduce inherent quality control deficiencies. The stacked plastic sheets tend to stick together and are hard to separate. Poor orientation of the sheet in a box also defeats the sealing effect desired.

OBJECTS AND SUMMARY OF INVENTION It is therefore a general object of the present invention to provide an improved liner for a packing box.

It is another object of the invention to provide a liner which is easily and rapidly installed in the box with automatically correct orientation.

It is another object of the invention to provide a liner which is originally folded but is easily unfolded.

It is another object of the invention to provide a liner which is designed to be transported in bulk form but is ready for instant use by the packer.

In accordance with the above objects there is provided a liner for a packing box having a pad therein for cushioning items packed in the box. The liner is attached to the pad. The pad has length and width dimensions corresponding to the interior of the bottom of the box. The liner is composed of a relatively fluid impervious plastic having a kinetic coeflicient of friction of less than .30. The liner is folded flat against the pad and forms a continuous surface having two ends which are contiguous and coincide with a predetermined axis which is parallel to a predetermined pair of sides of the box. The folded liner is capable of being unfolded by application of a tension force at each of its two ends.

3,519,160 Patented July 7, 1970 ice BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a packing box having a pad and liner therein in accordance with the present invention.

FIG. 2 is cross-sectional view taken along line 2.2 of FIG. 1, and additionally illustrating the use of the pad and liner in a packing operation.

FIG. 3 is an exploded view in perspective of FIG. 1.

FIG. 4 is a partial cross-sectional view of a box showing fruit therein in a completed, packed state.

FIG. 5 is an exploded view of FIG. 4.

FIG. 6 is a perspective view showing a portion of the manufacturing equipment used in making the liner of the present invention.

FIG. 7 is a perspective view of apparatus used in a method of fabricating the improved liner of the present invention.

FIG. 8 is a perspective view in very simplified form of a baling press used in preparing the liners of the present invention for shipment.

DETAILED DESCRIPTION OF INVENTION Referring now specifically to FIGS. 1 and 3, a wooden fruit packing box 11 having predetermined length and width interior dimensions has fitted within the box a liner 12 which as best shown in FIG. 3 is composed of two parts, namely, a folded polyethylene plastic film portion 12a which has been glued or fixed to a supporting cardboard type pad 12b having substantially the same dimensions as the folded film 12a.

The polyethylene film 12a is preferably a film of the type described in the United States Department of Commerce Commercial Standard Booklet on polyethylene film CS 227-59. This film is readily available from numerous manufacturers. In accordance with those standards the film is of the high clarity, high impact resistant type which has been treated for ink adhesion and has a high slip characteristic. Slip refers to the kinetic coefficient of friction of the film, or in simpler terms to its stickiness, which determines, of course, its handling characteristics. It has been found that a film having a kinetic coefficient of friction of less than .30 is suitable for the purposes of the present invention as will be outlined in detail below. The thickness of the film is preferably about .001 inch.

Other requirements of the film are that when used for food packaging it must be acceptable under the regulations for example of the Food and Drug Administration. Such a film, sold under the trademark of Polyfilm 217, is manufactured by the Dow Chemical Company.

The ink adhesion property of the film is usually achieved by either heat treating it or providing a corona discharge to allow the surface to adhere to such things as ink or glue. The latter is necessary in the present invention to enable the folded polyethylene film 12a to be glued to its cardboard support or pad 1212.

Although film of the above type is preferred because of its characteristics and cost, other films such as vinyl may be equally suitable for certain applications. All that is necessary is that the film be reasonably fluid impervious to provide a barrier to the passage of both liquids and gases including water, water vapor and gases such as sulfer dioxide and to provide a film having a kinetic coeflicient of friction of less than .30. This coefiicient of friction includes all high slip polyethylene film, as specified in the Department of Commerce standards, and in addition overlaps somewhat the medium slip grade. For the purposes of the present invention, a coefiicient of about 0.30 represents an upper limit.

Referring once again to FIG. 3, the polyethylene film liner 12a is folded flat against the pad 12b and has two ends 13 and 14 which are contiguous and coincide with a predetermined axis which is parallel to the side 16 and 17 of box 11. It is apparent that liner 12a forms a container surface which terminates at the ends 13 and 14. Also the liner has folded portions 18 and 19 which allow it to be unfolded as best illustrated in FIG. 2, so that the combined length of the flaps 21 and 22 in FIG. 2 will be sufficiently long to compensate for the height of the walls 16 and 17 of the box and in addition to overlap the two ends sufiiciently to provide a fluid impervious seal.

Because of the high slip characteristics of the polyethylene film 12a, a fruit packer with hands 23 may reach into the box as illustrated in FIG. 2, grasp the ends 13 and 14 with a thumb action and easily unfold the liner by application of a tension force to the ends 13, 14 of the liner. In contrast, when a polyethylene liner with a coefficient of friction greater than .30 is utilized, the worker will encounter a relatively difficult time in catching the edges 13 and 14 and unfolding the plastic. Moreover, as will be discussed below, the liner 12 is preferably baled into relatively small packages for shipment so that the baling action itself would aggravate the problem of stickiness due to an excessive coefiicient of friction.

As best shown in FIG. 3 a cushioning pad 24 may be provided at the bottom of the box intermediate the liner 12 and the box bottom to give additional cushioning where necessary. Such a cushion may be a pad filled with bark fibers as disclosed and claimed in US. Pat. No. 3,042,977 in the name of N. V. Poletika et al. and assigned to the present assignee. Alternatively, pad 24 may be substituted for the cardboard support pad 12b.

Thus to review the steps in packing for example nectarines in a packing box, the fruit packer would first obtain a box 11, place a pad 24 in the bottom if necessary, and then from an adjacent stack procure a liner 12 and place it in the box as illustrated in FIG. 1. Because of the corresponding dimensions the liner is automatically oriented. Next the packer using his thumbs obtains the edges 13 and 14 and opens the flaps of the liner as shown in FIG. 2. The box ready to receive fruit is now shown at 26 in FIG. 5. FIG. 4 shows the cross-sectional view of the completed packed box. The packer after opening the plastic liner places in the bottom of the box a fruit receptacle 27 in which he then places fruit 28 such as nectarines. A second fruit receptacle 27 is placed in the box and a second layer of nectarines packed. The two fruit receptacles may be separated by an additional cushioning layer 24 if desired.

Waxed cardboard side inserts 31 and 31' are inserted along the other two remaining sidewalls of box 11, a cushion 24' placed over the two flaps and the fiaps of the liner then folded over each other to provide an impervious fluid seal. Such a flap is shown at 21 in FIG. 4. Lastly a box top 32 is affixed to the box to complete the packing.

Liner 12 is manufactured and baled as best shown in FIGS. 6 through 8. The polyethylene plastic film is extrudecl from a device 33 in a tubular form 34 and indented by fingers 35 to provide inwardly folded portions 18 and 19. A knife 36 concurrently slits the tube 34 just before reaching rollers 37 to provide the ends 13 and 14. After passing through rollers 37 the film is rolled on a form 38 and is in the form of the polyethylene folded liner 12a, as shown in FIG. 1. Roll 38 is then fed into a second operation shown in FIG. 7 which has as object the gluing of the cardboard support pad 12b to it and the slicing of it into appropriate segments to fit the box 11. Material on roll 38 is tightened by tightener rollers 39 and the underside of the film 12a is sprayed with glue from the glue guns 41 and 42. At this point cardboard pad material 12b is fed into Teflon rollers 43 along with the film 12a to cause the two to adhere to each other. A rotating knife structure 44 slices the combined structure which is now liner 12 into the appropriate length segments and deposits them on a receiving table 46. Baler apparatus 47 compresses a suitable number of the liners 12 for subsequent shipment to the fruit packing operation. Such compression may reduce a stack of liners 12 which is five feet in height to a height of 28 inches. However, this extreme compression is not deleterious to the liners 12 because of the high coeflicient of kinetic friction material used which prevents excessive sticking. Thus, when a stack of liners is placed next to the fruit packer for his use, they are easily separated from each other and the liner is capable of being unfolded very easily.

In summary therefore, the present invention has provided an improved liner for a packing box which is easily installed in the box with automatically correct orientation, is easily unfolded by the packer of the box, and is designed for transportation in bulk form without deleteriously affecting the above qualities.

We claim:

1. A liner unit for use in a packing box for cushioning items packed in the box and for preventing the passage of moisture out of said box when packed, said liner unit comprising a relatively rigid pad having a rectangular configuration, a liner composed of a relatively fluid impervious plastic having a kinetic coefiicient of friction of less than 130, said liner being folded upon itself against said pad and having a portion thereof affixed to said pad and forming a continuous surface having two ends which are contiguous and coincide with a predetermined axis which is parallel to a predetermined pair of sides of said rectangular pad, said folded liner being capable of being unfolded by application of a tension force at each of said two ends.

2. A liner unit as in claim 1 which is pressed flat before use.

3. A liner unit as in claim 1 in which said plastic is polyethylene film having a high slip characteristic.

4. A liner unit as in claim 1 in which said folded liner is folded equally along each of its halves to provide for a sufiicient flap length when unfolded so that its ends overlap each other when folded over items packed in said box.

References Cited UNITED STATES PATENTS 2,005,594 6/1935 Ridgeway. 2,009,564 7/ 1935 Ridge. 2,172,332 9/1939 Rohrbacher. 2,287,495 6/ 1942 Moyers. 2,700,877 2/ 1955 Sambrailo.

RAPHAEL H. SCHWARTZ, Primary Examiner US. Cl. X.R.

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